Mascara brush



FIG. 1 is a perspective view thereof;

FIG. 2 is a front view thereof;

FIG. 3 is a side view thereof;

FIG. 4 is the other side view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines shown in the drawings illustrate portions of the mascara brush that form no part of the claimed design. 

The ornamental design for a mascara brush, as shown and described. 